A/C Pressure Switch

NOTE: The ACPSW may also be referred to as refrigerant containment switch.

The A/C Pressure Switch (ACPSW) is located in the high pressure (discharge) side of A/C system. Normally closed contacts in ACPSW open when A/C head pressure reaches maximum level, which turns off A/C by opening the A/C demand circuit and prevents A/C high pressure relief valve from opening. PCM modifies automatic transmission shift scheduling when A/C is on and KOER On-Demand Self-Test and Cylinder Contribution Test (CCT) are aborted. On Excursion, vehicle may be equipped with optional Electronic Automatic Temperature Control (EATC) system.